Automatic ventilating shutter



April 29, 1952 w LIQHMAN, JR 2,594,944

AUTOMATIC VENTILATING SHUTTER Filed Dec. 15, 1948 E Ii;

INVENTOR. MZZ 'am; cflovyalz 7 J",

s'hutter "comprises "a preferably Patented Apr. 29, 1952 AUTOMATIC VENTILATING SHUTTER William J. "Lohman, Jrl, Morristown, N.-J., a-ssignor to ChelseaProducts,.Inc.,.Irvington, N. J

a. corporation of New J erscy v lApplicationDecember 15, 1948, SeriQal NHL-65,319

This invention relates to'automatic ventilating shutters of the'type which'are self-closing butwhich open inresponse to the pressure of "airflow directed against the inner side thereof,

as e. 'g. by the operation of a ventilating fan.

The invention has for an object to provide an improved construction of automatic ventilating shutter of the kind stated which is especially adapted for horizontal installation in ceilings or like locations, and which comprises a-series of interconnected pivoted louvers coun- "terbalanced to'close by gravity, additional means "being provided, which is operative when the louvers are open, to exert upon the open louvers an initial closing thrust independent of gravity, whereby to positively initiate closing movement er the 'louversw'hen pressure of air flow against "the inner sides thereof is interrupte'd,'thus pre- "is shown in the accompanying drawings, in

"which:

1 is'an exterior plan view than auto- "matic ventilating shutter according to the invention, the same being shown in normal closed 'conditionjFigy 2 is 'a longitudinal sectional view of the same, taken on line '2-2 in Fig. 1; Fig.

"3is a fragmentary longitudinal sectional 'view of the closed ventilating shutter similar to that 'o'f'Flg. '2, but drawn on an enlarged scale; and

Fig. 4 is a view similar to that of Fig.3, but showing the'ventilating shutter in fully open condition.

Similar characters of reference'are employed in the above described views, to indicate corresponding parts.

Referring to the drawings, the ventilating rectangular "frame formed by side walls '10 and end walls H, and which is provided with a surrounding outwardly extending base flange l2.

Pivotally mounted within the frame are a series of shutter members which are preferably arranged to extend across the frame between the'side walls In thereof.

"Each Jshutter member comprises "a suitably shaped carrier bracket l3 having hinge ears l4 projectingfrom opposite ends thereof at points adjacent the forward or outer margin of the same. Said 'ca'rrier bracket-"ls prefei ably inade or comparatively heavy stamped sheet pineal.

Mounted on the carrier bracket I3-is alouver l 5 which is preferably made of lightsheet m'etal,

such e. g. as aluminum, but which may, if desired, be made of other material, such' asp'r'essed wood, sheet plastic material, or the-like. The louver I5 may be affixed to and so as -to be unitary with the carrier bracket 13 many suitable manner and by any sui'table'means. 'Ill'ustratively, as shown, the rearward longitudinal marginal portion of'the louver I5 is secured-to the carrier bracket by a clamping clip portion 1 5 which is doubled back from the inner or-r'earward longitudinal margin of the carrier bracket, so as to embrace and grip said-rearward'longitudinal marginal portion of the louver. The louver I5 is further secured to the carrier bracket by fastening lugs I! which extend from-'the-ends of the latter and which are iii-turned overand around the ends of the louver.

The shutter members are pivotally supported within the frame by pivoting cross rods [8' which are affixed to the frame to extend between the side walls In thereof, and which pass through the hinge ears [4 of the carrier "brackets l3. The spaced relation of the shutter members'is such that, when the same are closed, the-forward or outer longitudinal marginal "portions of the louvers 55 will lap the rearward or inner marginal portions of next adjacent louvers. If desired, the forward or outer longitudiri'al'rnargins of the louvers l5 may be edged-with flexible sealing material I9, suche. g. as a strip of felt, rubber or similar material. Said flex-- ible sealing materiallfi may be secured to the louver edges by anysuitable holding or fastening means.

The shutter members are suitablylinked together so as to simultaneously move to their open or closed positions. The means for so linking the shutter members comprises the provision of'a lever'arm'Zi! which is affixedtoftlie. free 'or'outer face or side thereof. 'Ihes'elever arms 20 are coupled one to'another by "a com- .mon tie bar or link 2| to which'the ends of the lever arms are pivotally connected.

The hinge ear M of the carrier brackets I3 are disposed in forwardly offset relation to the fully calculated so that, although the louvers l will tend to move to closed position under gravity, 1. e. have a slight closing bias when in or near closed positions, yet the balance is such that the louvers will readily respond to the thrust of air flow pressure directed against their inner faces, so as to quickly and easily open under the influence of suchpressure.

It has been found, especially when the ventilating shutter is horizontally disposed, as in the case of a ceiling installation thereof, that, under strong air flow pressure, the louvers swing up to an upstanding fully open position (as shown in Fig. 4), the weight of the free end portions of the louvers l5 together with that of their lever arms 20 and the interconnecting tie bar or link 2|, may be carried across a dead center line perpendicular to the pivotal points of the shutter members a provided by the cross rods l8, with the consequence that gravity cannot properly exercise its force to initiate closing movement of the shutter members when air flow pressure against thelatter ceases. This opening bias is, of course, undesirable, and to overcome the resultant tendency of the shutter members to stall in open positions under such circumstances, the instant invention provides means to initiate a closing thrust against said shutter members when air flow pressure is reduced or ceases. This means comprises a special form of suitably located spring member having a base or butt section 22 which is suitably affixed to the inside surface of an end wall ll of the frame exteriorly of the shutter members. Said base or butt section 22 terminates in a convolute section 23, providing at least one convolution, from the outer end of which extends an elongated free end portion or arm 24. The free end portion or arm 2 of the spring member extends over the louver l5 -of the-shutter member which is adjacent said end wall H, so as to bear against the same at a point outwardiy or forwardly of the pivotal connection of said shutter member to the frame.

Whenthe shutter members are disposed in closed positions, the convolute section 23 of the spring member is expanded and substantially. fully relaxed, so that the spring member exerts practically no tensional thrust upon said shutter members, and consequently offers but little resistance to initial opening movement of the shutter members under the thrust of air fiow pressure upon the inner faces thereof.

-When the shutter members swing up to open under the thrust of applied air fiow pressure, the arm 24 of the spring member i also upswung with the shutter member engaged thereby. The effect of such upswinging movement of the spring member arm 24 is to exert a contractive winding torque upon the convolute section 23 of the spring member, which, as such upward movement continues, gradually increases the reactive .tension of the convolute section. The tension of the convolute section 23 accumulates so gradually that it offers but little resistance to initial and intermediate phases of the opening movement of the shutter members in response to the applied air flow pressure. When, under strong, air flow pressure, movement of the shutter members disposes the same in an upright fully opened condition (as shown in Fig. 4), wherein gravity closing may be impeded as above explained, the

convolute ection 23 of the spring member will have been wound to maximum tension. When the tension of the convolute section 23 is thus at a maximum, such tension is suincient to exert an initial closing thrust upon the shutter members which i strong enough to overcome any tendency of the latter to stall in fully open condition after air flow pressure upon the same ceases.

Preferably the spring member is formed from a thin strip of spring steel or the like, since such form thereof is best adapted to provide desired flexibility and low or light tensional reaction such as to offer but little resistance to shutter opening movements, and yet under a condition of maximum stored tension sufficient to effect the desired initial closing thrust upon the fully open shutter.

Having now described my invention, I claim:

1. An automatic ventilating shutter for ceiling installation comprising a vertically open horizontal frame, a plurality of parallel louver members pivotally mounted across the frame opening on longitudinal axes lying substantially in a horizontal plane to swing upward and outward from lapped closed positions toward upstanding open positions under the influence of upward air flow through said opening, each louver member being constructed and arranged in relation to its pivotal axis to provide a free upwardly opening portion extending forwardly from said axis and a counterbalancing portion extending rearwardly therefrom, a tie-rod linking the forwardly extending portions of all louver members for simultaneous opening and closing movements and being disposed with its weight supported by said forwardly extending portions and thereby tending to close the same, each rearwardly extending portion of the louver members counterbalancing the weight of the forwardly extending portions of the tie-rod to afford slight closing bias to said louver members with their tie-rod load when in or near closed positions and to afford opening bias when in fully open positions, and spring means for resisting opening movement of the louver members and operable to overcome the opening bias produced by the counterbalancing portions thereof upon cessation of airflow.

2. An automatic ventilating shutter as defined in claim 1, wherein the spring means cooperative with the louver members is in the form of a leaf spring having a base affixed to the shutter frame adjacent to the rearwardly extending portion of a terminal louver member, said spring having an arm extending substantially horizontally in overlying relation to said terminal louver member in relaxed condition with its free end bearing against the upper surface of the forwardly extending portion thereof comparatively close to the pivotal axis thereof and adapted for sliding contact with said surface during louver opening and closing, whereby the contact will be at a location more remote from the pivotal axis when the louver is open to increase the leverage of closing action.

3. An automatic ventilating shutter as defined in claim 1, wherein the spring means cooperative with the louver members is in the form of a leaf spring having a base aflixed to the shutter frame adjacent to the rearwardly extending portion of a terminal louver member, said spring having an arm connected to the base thereof by a convolute section and normally supported thereby in substantially parallel relation to the said terminal louver member in overlying relation thereto with its free end bearing against the upper surface of the forwardly extending portion of said louver member, said spring being in relaxed condition when the louver members are closed and in contact with said terminal louver member at a location comparatively close to the pivotal axis thereof and being adapted for sliding contact therewith during louver opening and closing, whereby the contact will be at a location more remote from the pivotal axis when the louver is open to increase the leverage of closing action and whereby flexing of the spring will be restricted principally to the convolute section thereof.

4. An automatic ventilating shutter as defined in claim 1, wherein the means for pivotally mounting each louver member includes hinge ears affixed to said member and disposed to project downward when the louver member is in closed position and having their free ends pivoted in the shutter frame, whereby when the louver members are fully open the weight of each of said members and a proportionate part of the weight of the tie-rod will be supported by the hinge ears as substantially horizontal lever arms to increase the leverage of opening action.

WILLIAM J. LOHMAN, JR.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 158,630 Dougherty Jan. 12, 1875 1,424,410 Hopewell Aug. 1, 1922 2,060,289 Downs Nov. 10, 1936 2,061,162 Mader l- Nov. 17, 1936 2,103,982 Hart et al. Dec. 28, 1937 2,135,810 Germonprez Nov. 8, 1938 2,191,774- Reed Feb. 27, 1940 2,295,239 Seator Sept. 8, 1942 2,314,003 Mader Mar. 16, 1943 2,323,178 Denman June 29, 1943 2,355,412 Bird Aug. 8, 1944 FOREIGN PATENTS Number Country Date 12,742 Great Britain 1904 574,975

Germany Apr. 21, 1933 

